Is lenticle a word in the Scrabble Dictionary

No, lenticle is not playable

...but would be worth 10 points.

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SOWPODS (Collins Scrabble Words)

"Lenticle" Definition

noun

In geology: a stratum of sedimentary rock. which from its central point of maximum thickness tapers to a thin edge in every direction; a common form of limestone in shales.
A mass of eruptive rock squeezed and sheared into a shape like the typical sedimentary lenticle.